Apparatus for dry generation of acetylene



Feb. 13, 1940.

M. o BRIAN APPARATUS FOR DRY GENERATION OF ACETYLENE Filed Aug. 27, 19372 Sheets-Sheet. 1

INVENTOR MAURiCE OBRIAN ATTORN EY Feb. 13, 1940.

' M. OBRIAN APPARATUS FORDRY GENERATION 0F ACETYLENE Filed Aug. 27',1957 2 Sheets-Sheet 2 INVENTOR MAURICE O'BRIAN ATTORNEY tained a body ofcalcium hydrate in a desired Fatented Feb. 13, 1941! APPARATUS FOR DRYGENERATION OF ACETYLENE Maurice OBrlan, Indianapolis, Ind., assignor toThe Prest-O-Lite Company, Inc., a corporation of New York ApplicationAugust 27, 1937, Serial No. 161,175

14 Claims.

This invention relates to apparatus for producing acetylene and anyhydrated lime residue by the reaction of calcium carbide with limitedquantities of water, and more particularly to means for separatingparticles of hydrate from acetylene produced by the so-called drygeneration of acetylene. v

Generally, the bject of the present invention is to provide an provedarrangement of apparatus for scrubbing the acetylene produced whencarbide is reacted in a so-called dry generator so as to eflicientlyproduce acetylene and also recover a substantially .dry commerciallyuseful calcium hydrate residue in powdered form.

More specifically, objects of the present in-. vention are: to providean apparatus of the character indicatedin which the acetylene producedwhen reacting calcium carbide in 'a reaction chamber with such a limitedquantity of water that dry powdery calcium hydrate is simultane ouslyproduced and which carries entrained particles of the hydrate, may bescrubbed clean of suchparticles; by which the acetylene may beeffectively cooled to a desired temperature; by which large quantitiesof water vapor may be removed from the acetylene; by which water isprevented from reaching the dry calcium hydrate powder'being produced;and by which plugging, by. sediment, is prevented.

These and other objects of the invention and the novel features thereofwhich achieve these objects will become evident from the followingdetailed description taken in connection with the accompanying drawingsin which:

Fig. l is an elevational view, partly in section, of an apparatus forgenerating acetylene with the production of a substantially dry residue,having gas scrubbing means constructed ac-. cording tothe presentinvention;

Fig. 2 is a view of a section of the apparatus shown in Fig. 1 taken onthe line 2-2; and

Fig. 3 is an elevational view of the rotating agitator device shown inFig. 1.

In the co-pending application Serial No. 103,526, filed October 1, 1936,in the name of Charles Ness jointly with H. V. Kojola, there isdescribed a method of and apparatus for the dry generation of acetylenewhereby carbide is fed into a reaction chamber into which controlledamounts of water are introduced and in which is maindry andfiuid-likecondition. Carbide and water continuously introduced into thereaction chamber, react forming acetylene and more hydrate.

The carbide introduced, together with the newlyformed hydrate, causes anupward displacement of the body of hydrate, while the gas producedpasses upward through the body of hydrate to assist in maintaining itsfiuidelike condition. At I the top of the reaction chamber the majorpart of the hydrate produced overflows and is withdrawn from furthercontact with the gas which is collected above the reaction chamber andwithdrawn to a gas holder. The contents of the re- 10 action chamber arepreferably continuously agitated by mechanical means to accelerate thereaction; to insure complete contact of carbide with water; to efiectthe classification of the materials to insure that carbide will flowdownward and displace hydrate upward: and to avoid the formation ofzones of local high temperature. The amount of water added issufilciently in excess of that needed for completing the reaction tocontrol by its evaporation the average go temperature of the contents ofthe reaction chamber to within desired limits.

The water that is vaporized passes ofi with the gas and means must beprovided for removing vapors from further contact with the residue 25 assoon as the residue leaves the reaction chamber where it was maintainedat a uniform high temperature and before the vapor is cooled so as toavoid condensation of moisture on the hydrate. action chamber does notremove all of the finer particles of calcium hydrate entrained in thegas produced. Therefore, according to the present invention, theremaining extremely fine particles are removed by causing the gas topass 35 collecting the dry residue. The reaction chamber 5 B of theapparatus shown comprises the lower portion lot a closed generatorcasing II. The portion l0 has the form of an inverted, hollow, truncatedcone whose larger end is open and projects upwardly into an enlargedportion of 50 the casing l2 wherein the gas produced separates from mostof the finer particles of residue which may have been carried upward bythe gas. The gas produced is ledoff from the generator. through aconduit l3, which connects ,to the pipe line The settling chamber abovehe re- 30 N that conducts the gas to storage means, such as a gasometer,which is not shown in the interest of cleamess of the drawing.

The carbide is fed into the reaction chamber B near the bottom thereoffrom the carbide supply means A. The upper chamber I2 comprises an opentop tank having a bottom through which the reaction chamber In passescentrally so as to form an annular lime collecting space or compartmentl5 surrounding the upper part of the reaction chamber. At a point nearthe top rim of the tank N, there is provided an annular open top chamberI6 outside of the tank H which has a closed bottom i! that is welded tothe outside wall of the tank. Outside of the annular chamber I6 isdisposed an annular water seal chamber l8 having a closed bottom I! thatis welded to th'eside of chamber IS. A sheet metal cover for the tank His provided having a depending cylindrical skirt portion 2| that extendsdown into the water seal I8 to a point close to the bottom l9 thereof.The cover 20 is formed higher in the central portion so that moisturethat condenses thereon will flow to the edges and run into the seal II.The top of the water seal I8 is closed by an annular ring 22 which iswelded to the upper edge of the seal II and to the upper portion of theskirt 2|. An apron or baffle 23 surrounds the upper edge of the tank Iin order to prevent particles of lime from falling down into the annularchamber ii. The lower edge of the skirt 2| is serrated, as shown at 24,for the purpose of providing an even distribution of, and to cause thebreaking up into small bubbles of the gas that flows under the edge ofthe skirt 2| through the water seal |8.. The water seal l8 thusconstitutes ran integral scrubber for the gas produced which from thespace above the water in*'-the scrubber through the outlet connection|3-and conduit l4.

The agitating mechanism, shown more clearly in Figure 3, comprises aframe that rotates about a vertical axial shaft 25;" A short hollowshaft 26 that passes through the bottom of the reaction chamber has anupper end which is joined to the central hub of a cross-arm 21 whoseouter ends are fastened to two upwardly extending members 28 of the mainagitator'frame. A plurality of spaced cross-arms 29 parallel to the arm21 are also provided joining the members 23. The members 28 are arrangedto closely follow the inner wall of the reaction chamber II and theirupper ends, which extend just above the upper edge of the reactionchamber, are joined by a horizontal cross member 30. The member 30 is solong as to almost touch opposite portions of the wall of tank Secured toeach end of the cross member 30 are two vertical scraper bars 3|. Thesebars follow closely the unitary cylindrical inner wall of the tank II toprevent any adherence of lime thereon and may have bevelled edges tofacilitate the removal of lime. The bars 3| extend slightly above theedge of the tank II where they are joined by anupper cross member 32whose ends extend to within a short distance from the unitarycylindrical wall of the skirt 2|. The members 33, 3|, and 32 aremaintained in the desired relation by two the members 21, 29, u, and :z.These hubs have j Ihores [which freely rotate upon the span fljvhichX-shaped cross frames 33 and 34 whose ends are welded to the members 30and 32. Hollow hubs are provided at the central portion of each ofpasses axially thrcugh'the generatorin the vertiy' cal direction.Bcrapersfor stirring the limethat collects in the annular chamber I5 areprovided by the depending bars 35 whose lower ends are joined to thelower ends of the vertical members 3| by cross bars 36 and whose upperends are welded to the cross member 30. The cross bars 36 may also havetheir leading edges bevelled for scraping the lime. Means is alsoprovided for stirring the water in the scrubber water seal 18. Thismeans comprises two pairs of vertical bars 31, each pair fastened toeach end of the member 32 and having their lower ends attached to ahorizontal scraper 38 which closely follows the bottom I9 01 the waterseal.

The hollow shaft 26- projects through a sealing means in the bottom ofthe reaction chamber to prevent lime from the reaction chamber fromgetting into the gear box 40 and is turned by bevel gears located in agear box 40 below the reaction chamber, the power being supplied to thegears by the power output shaft 4| of a speed reducer 42. An alarm bell43 is provided to indicate that the outer paddle assembly carrying thescrubber scraper 32 is operating properly. To this end, the bell 43 ismounted on a horizontal shaft 44 which passes through a seal bearing inthe cylindrical outer wall of scrubber chamber II. The inner end ofshaft 44 carries a long dependent arm 45 reaching almost to the bottomIQ of the scrubber so that the lower end of the arm 45 is struck by eachof the members 38 as the agitator revolves. The weight of the bell andthe arm 45 cause the arm to return to the vertical position afterdisplacement by the scrapers 33.

The carbide is introduced into the reaction chamber I by means of theconveyor operating in the housing 46 whose outlet end connects with thechamber l0 and whose other end is connected to the outlet 41 of acarbide hopper 43. The outlet 41 is controlled by a sliding type valve49. A second carbide supply hopper 50 is disposed above the hopper 48,with a connection between the hoppers controlled by a second carbidevalve 5|. The hopper 5|! is sealed by a lid 52. The shaft 53 of theconveyor passes through a stufllng box 54 in the end of the housing 46and has an outer end which is journaled in the top bearing carried bythe bearing support 55. A gear 55 is mounted on the shaft 53 and drivenby an intermediate gear 51 mounted on a countershaft 58. Theintermediate gear in turn is driven by a gear 58 on the shaft 4|. Thecountershaft II has its ends journaled in a bearing in the hearing stand55 and in a bracket bearing 6|) which is mounted in-a support thatdepends from the underside of the housing 46. Another and largerintermediate gear 6| is also mounted on the shaft 58 and a correspondingsmaller gear 62 is slidingly mounted on the shaft 4| in such a way thatit may be shifted into engagement with the gear 3| or out of engagementtherewith as desired. ,4 The hubs of gear 59 and gear I are joined by asleeve and both may be shifted simultaneously along the shaft 4| so thatthe countershaft 53 may be driven by either gear 53 or gear 62. Sincethe gears 52 and 62 are of different size, the shafts 53 and 53 will bedriven at different rates of speed according to the gear ratio selected.The rate of feeding of carbide may thus be varied as desired to changethe rate of gas production. The shaft 4| passes through the lower in thebearing stand 55 and is connected-totheoutput side of the speed re- 1 I42which isdriven by the electric motor 33.

' 'dry"residue produced which :5

collects in the annular compartment I5. is moved Wild 9 the arms 35 andscrapers it so that it the bottom of, and communicating with chamber 05so as to receive the residue. The lower end of chamber 64 communicateswith a lime conveyor 65 that withdraws the hydrated lime that Y tainedin the chamber 64. This seal is providedby maintaining a supply of thedry hydrate in the lower part of the chamber. To determine the 15,amount of residue collected in the chamber. N, there is provided anindicating means in the form of a rod 56 having at its lower end a disktil and at its upper end a handle 68. The rod 5 through the top of thechamber dd through a stufiing box and by moving the rod as up and downthe height of the lime in the chamber may be readily determined. Theoperation of the conveyor $5 is thereupon so controlled that a supply oflime is caused to remain in the lower part of the chamber to maintainthe seal.

The water required for the reaction and for absorption of excess heat isadded at points 69 close to the bottom of the reaction chamber 50. Therate of flow of the water supply may be deao termined by means of a flowmeter comprising an orifice and manometer or by any means formaintaining a regulatable constant supply of water such, for example, asa positive displace- ,ment pump whose speed of operation may beregulated.

A supply of water is added to the scrubber seal it through a connectionit which is located in the cover 22 of the seal. Excess water normallyflows out of the seal through the gas outlet connection it which isconnected to the outer wall of the seal it at a desired point. Thisoverflow water runs along the bottom of connection l3 and conduit l4until it reaches a draining conduit Ii depending therefrom. The annularchamber i6 is provided so that water which might be driven backward byan abormnal backflow of gas through this scrubber will be caught by thechamber 16 instead of being carried into the chamber l2. Such backflowof water may also be caused when the generator is shut down from theoperating temperature and the resulting contraction will reduce thepressure to a 5 degree that may be suficient to cause a backflow ofwater. The contraction may'even be great enough to cause a backflow ofgas under the skirt 2i and it is desirable that this shall occur beforethe pressure in the generator is .reduced substantially belowatmospheric to avoid the occurrence of a subatmospheric'pressure thatmight tend to draw in air or cause injury to the generator casing. Toremove water that may reach the chamber it, there is provided a drainconduit it. connected to he lower part of the chamber i6 and dependingdown intola water seal it. The depth of the seal is is sumcient toprovide a head of water greater than the normal head of pressure of thegas in the generator. The

conduit H also depends into the water seal T13 to a depth sufllcient toprevent the escape of gas when under the normal pressurev in the conduitan Rhmflri this nressnrebe substantially exwithout draining the scrubberseal it because the gas'remaining in the generator will cool down seal13 is provided with an overflow drain 14 and a vent pipe it, bothconnected to the upper porconnected to the lower portion for cleaningout lime that may settle to the bottom. A valve controlled drainconnection 11 is also provided and connected between the bottom of thechamber l8 and the conduit 12. The valve in connection 11 is opened whenit is desired to drain water from the chamber l8.

Rotation of the paddle assembly keeps the body of carbide and hydrate inthe reaction chamber thoroughly agitated while the gas and vapor flowingupward assists the agitation and tends to" make the hydrate morefluid-like. The carbide particles remainin the chamber l0 until consumedbut the hydrate overflows the top of the chamber iii and fallsinto theannular compartment is. Here the hydrate is stirred and swept around bythe scrapers 35 so as to fall into the hopper 64, from which it'iswithdrawn by conveyor 55 as a rate such as to maintain a plug of hydratein the bottom of the hopper so that gas will not escape to the conveyor.Any other means for effecting a gas seal while withdrawing the hydratemight be used.

The acetylene and water vapor are released at the top of the reactionchamber into the relatively large space H above formed by the tank 8 Iand cover 20. In this space the velocity of flow is so reduced that theliner particles of hydrate settle down and the gas flows over the upperedge of tank ll, down between skirt 2i and chamber wall i6 and upthrough the scrubber water in the space between skirt 2| and the wall ofseal it. The serrations 24 cause the gas to pass in very small bubblesproviding thorough contact with the water in the seal which consequentlyremoves the last traces of hydrate and cools the gas to a desiredtemperature. A substantial portion of the vapor carried by the gas iscondensed and flows of! with the overflow water of the seal.

When first starting up the generator, the motor 63 is started, water isadmitted at a constant rate to the scrubber at inlet 10 and the carbidevalve 49 opened. When carbide enters the chamber l0, admission of waterat a constant rate thereto is begun. When shutting down the generator,the carbide valve 49 is first shut off, the water is allowed to enterfor a specified period of time and is then shut off and the paddles arekept turning for an additional period to insure that the moisture isevenly distributed and dispersed. The generator may then stand idle fora period without danger of lime caking in the reaction chamber.

The arrangement of the scrubber, according to the invention, in the formof an integral annular chamber about the upper rim of the chamber 92provides a highly efiectivescrubber for the gas. The scrubber is compactand requires little additional space but the length of the edge is underwhich gas is passed is relatively very great so that large volumes ofgas may be efliciently scrubbed. The serrations of the edge 24 and thelength thereof cause the gas to be broken up into a large number of veryfine bubbles so that effective contact with the water in the chamber 18is assured. The lime dust carried by the gas is eflectively washed out;the gas is effectively cooled; and excess moisture is condensed. Thethorough cooling of the gas causes water

